Maintaining a Klarus ST10

[DreadArchon]

I got my first more-than-$10 flashlight about a month ago, a Klarus ST10. It's good when it works, but right out of the box the highest modes were often buggy, and it's not really getting better.*

It acts a bit like a horror movie flashlight, barely turning on and/or flickering and dying at an inconvenient moment and I have to play with it. Again, this is mostly at high powers, but sometimes I have to turn it off and on a couple of times to get lowest powers to stay too.

Suggestions?

I don't have a DMM right now, but I can get access to one soon.

Battery is an Eneloop (single AA).
Edit: And of course I have tried changing it out.



*I realize it's not reasonable to expect it to self-repair. For a while I thought I was just knocking loose the cap.

 

[RBWNY]

I would contact the seller and return it. Sounds like a bum light :shakehead. When I first got an ST20 (almost 2 yrs ago) it started acting weird (just like yours) after I had it only a couple weeks. I returned it, and was sent a replacement. It actually acted strange too --only briefly-- but since then has been just fine.

I have an ST10 as well but have never had an issue with it.